1. Field of the Invention
The present invention relates to an electronic device, and more particularly, to an electronic device having an impact detecting function.
2. Description of the Related Art
When an impact is repeatedly applied through a machine casing to an electronic device, damage may be accumulated in electronic parts mounted on the electronic device or solder portions thereof, and thus, the electronic parts are destructed or the solder portion are broken, so that the electronic device may lead to failure. During the time interval from the occurrence of failure to the restoration, a machine tool cannot perform processing, and the utilization rate is lowered, a user experiences disadvantages.
Therefore, if an impact which is considered to cause failure can be detected and a worker or an equipment maintenance person can be prompted to change a processing condition, take measures to the impact of the machine tool itself, or improve a machine operating method, or the like, an operating time can be extended, and rapid restoration at the time of failure can be made by advance preparation of replacement parts, so that the utilization rate of the machine tool can be improved.
As impact generating factors, there are (1) an improper machining program causing an impact between a workpiece and a tool, (2) an improper processing condition such as discordance between a feed speed of the workpiece and a rotation speed of the tool, (3) a user's operation of the machine, and the like. With respect to the generating factors (1) and (2), improvement can be made by performing processing simulation using CAM software of a PC or the like before the performing of actual processing. However, with respect to the generating factor (3), prediction is difficult.
Among the aforementioned generating factors, as the generating factor (3) caused by the user's operation, exemplified is impact generation according to an operation of an electronic device itself or a device attached in the vicinity thereof, for example, pressing a button attached to the electronic device or opening/closing of a cover attached to the electronic device, or an operation of moving a safety door attached to the machine tool or an operation panel pendant attached with a controller.
The type of impact is different according to the generating factor, and in a case where the operation of opening/closing of the door or the operation of moving the operation panel pendant is the generating factor, since the entire casing of the machine tool is vibrated, members of the casing collide each other several times, so that a multiple-type impact is generated. On the other hand, in a case where the operation of the button or the operation panel is the generating factor, since only the electronic device itself or only the installed portion thereof is vibrated, the members of the casing collide with each other once, so that a single-type impact is generated. When two impacts having the same maximum values of acceleration are considered, the multiple-type impact applies stronger stress to the electronic device than the single-type impact.
In the related art, well-known is a method of mounting an acceleration sensor on an electronic device, detecting an impact after free fall or fall or both impacts thereof, and display warning to stop the device or record in maintenance information. Particularly, since a mobile electronic device is configured in a form that the electronic device is used while being carried, in a well-known method, a certain level of impact protection mechanism is provided, so that an impact capable of causing failure is detected.
In addition, for example, JP 2014-215184 A discloses a technique of measuring a free fall time and a convergence time of an impact observed after the free fall, comparing the time with an allowable convergence time every predefined free fall time to determine whether or not a certain impact is applied, by using an acceleration sensor.
However, only if the magnitude of the impact is identified and warning is issued based on a certain threshold value by using a mounted acceleration sensor, even in the case of the aforementioned small stress, a single-type impact is also detected, and in a normal operation, warning is frequently issued, so that user's convenience is impaired.
In addition, in a stationary-type electronic device such as a numerical controller which can be installed in a machine tool, free fall does not occur, and thus, the free fall time as a reference of determination of the impact does not exist, so that there is a problem in that it is difficult to identify and detect a degree or type of the impact.